Carbon-containing molybdenum and tungsten sulfide catalysts

ABSTRACT

Catalysts comprising a carbon-containing sulfide of molybdenum or tungsten are prepared by contacting, in the presence of sulfur, hydrogen and a hydrocarbon, ammonia and ammonium substituted molybdate, thiomolybdate, tungstate and thiotungstate salts at a temperature of from about 200°-600° C. These catalysts are useful for hydrotreating reactions. In a preferred embodiment, these catalysts will be promoted with certain transition metal sulfides, such as cobalt sulfide, which results in catalysts having greater activity than conventional catalysts such as cobaltmolybdate on alumina.

CROSS-REFERENCE TO RELATED APPLICATION

Continuation-in-part of U.S. Ser. No. 399,991 filed July 20, 1982, nowabandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to producing poorly crystalline,carbon-containing molybdenum and tungsten sulfide catalysts. Moreparticularly, this invention relates to producing poorly crystalline,carbon-containing molybdenum and tungsten sulfide catalysts bycontacting ammonium or substituted ammonium thiomolybdate orthiotungstate salts with a hydrocarbon, hydrogen and sulfur at elevatedtemperature.

2. Background of the Disclosure

The petroleum industry is increasingly turning to coal, tar sands andheavy crudes as sources for future raw materials. Feedstocks derivedfrom these heavy materials contain more sulfur and nitrogen thanfeedstocks derived from more conventional crude oils. Such feedstocksare commonly referred to as being dirty feeds. These feeds thereforerequire a considerable amount of upgrading in order to obtain usableproducts therefrom, such upgrading or refining generally beingaccomplished by hydrotreating which includes reactions such ashydrodesulfurization to remove sulfur compounds, hydrogenating tosaturate olefins and condensed aromatics and also hydrodenitrogenation.

Catalysts most commonly used for these hydrotreating reactions includethings such as cobalt molybdate on alumina, nickel on alumina, cobaltmolybdate promoted with nickel, etc. Also, it is well-known to thoseskilled in the art to use certain transition metal sulfides such ascobalt and molybdenum sulfides and mixtures thereof to upgrade oilscontaining sulfur and nitrogen compounds by catalytically removing suchcompounds in the presence of hydrogen, which processes are collectivelyknown as hydrorefining processes, it being understood that hydrorefiningalso includes some hydrogenation of aromatic and unsaturated aliphatichydrocarbons. Thus, U.S. Pat. No. 2,914,462 discloses the use ofmolybdenum sulfide for hydrodesulfurizing gas oil and U.S. Pat. No.3,148,135 discloses the use of molybdenum sulfide for hydrorefiningsulfur and nitrogen-containing hydrocarbon oils. U.S. Pat. No.2,715,603, discloses the use of molybdenum sulfide as a catalyst for thehydrogenation of heavy oils, while U.S. Pat. No. 3,074,783 discloses theuse of molybdenum sulfides for producing sulfur-free hydrogen and carbondioxide, wherein the molybdenum sulfide converts carbonyl sulfide tohydrogen sulfide. Molybdenum sulfide has other wellknown uses as acatalyst, including hydrogenation, and is also useful for the water gasshift and methanation reactions.

In general, with molybdenum and other transition metal sulfide catalystsas well as with other types of catalysts, higher catalyst surface areasgenerally result in more active catalysts then similar catalysts withlower surface areas. Thus, those skilled in the art are constantlytrying to achieve catalysts that have higher surface areas. Morerecently, it has been disclosed in U.S. Pat. Nos. 4,243,553, and4,243,554 that molybdenum sulfide catalysts of relatively high surfacearea may be obtained by thermally decomposing selected thiomolybdatesalts at temperatures ranging from 300°-800° C. in the presence ofessentially inert, oxygen-free atmospheres. Suitable atmospheres aredisclosed as consisting of argon, a vacuum, nitrogen and hydrogen. InU.S. Pat. No. 4,243,554 an ammonium thiomolybdate salt is decomposed ata rate in excess of 15° C. per minute, whereas in U.S. Pat. No.4,243,553, a substituted ammonium thiomolybdate salt is thermallydecomposed at a very slow heating rate of from about 0.5 to 2° C./min.The processes disclosed in these patents are claimed to producemolybdenum disulfide catalysts having superior properties for water gasshift and methanation reactions and for catalyzed hydrogenation orhydrotreating reactions.

SUMMARY OF THE INVENTION

It has now been discovered that useful carbon-containing molybdenum andtungsten sulfide catalysts are obtained by contacting one or morecatalyst precursors selected from the group consisting of (a) ammoniumthiomolybdate or thiotungstate salts, (b) ammonium molybdate ortungstate salts, (c) substituted ammonium thiomolybdate or thiotungstatesalts, (d) substituted ammonium molybdate or tungstate salts, andmixtures thereof, with sulfur, hydrogen and a hydrocarbon at atemperature broadly ranging from about 150°-600° C. This produces thecatalysts of this invention which have the general formula MS_(2-z)C_(z') wherein 0.01≦z≦0.5 and 0.01≦z'≦3.0. These catalysts are poorlycrystalline and have been found to have surface areas of up to about350-400 m² /gm. In a preferred embodiment of this invention, thesecatalysts will be promoted with one or more promotor metals such ascobalt. Such promotion of the catalysts of this invention has been foundto produce catalysts having hydrorefining activity substantially greaterthan that of conventional cobalt molybdate on alumina hydrorefiningcatalysts.

The sulfur that is required to be present during the formation of thecatalyst from the precursor salt may be present in the precursor saltitself (i.e., a thiomolybdate salt), provided that it is present in anamount sufficient to achieve the desired stoichiometry of the resultingcatalyst. In a preferred embodiment, sulfur will be present in thereaction zone in an amount in excess of the stoichiometrically requiredamount. Similarly, the hydrogen required may be present as gaseoushydrogen, or hydrogen-bearing gas such as H₂ S, one or more hydrogendonor hydrocarbons such as tetralin, or combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 graphically illustrate the unusual pore volumedistribution of two catalysts of this invention.

FIGS. 3 and 4 graphically illustrate the hydrodenitrogenation of a feedin contact with a catalyst of this invention formed from atetrabutylammonium thiomolybdate precursor.

FIGS. 5 and 6 graphically illustrate the hydrodenitrogenation of a feedin contact with a catalyst of this invention formed from atridodecylammonium molybdate precursor.

DETAILED DESCRIPTION OF THE INVENTION

Precursor salts useful in forming the catalysts of this invention willhave the formula B_(x) [MO_(y) S_(4-y) ] wherein x is 1 or 2 and y isany value ranging from 0 to 4 wherein B is (a) an ammonium ion, (b) analkyl or aryl diammonium ion, (c) an alkyl or aryl ammonium ion whereinsaid ion may contain from 1-4 alkyl or aryl groups and wherein M is Moor W. In a preferred embodiment y will be any value ranging from 0 to 3.Illustrative but non-limiting examples of suitable substituted aliphaticammonium ions include n-C₄ H₉ NH₃ ⁺, (C₂ H₅)₂ NH₂ ⁺, (CH₃)₃ NH⁺ and(CH₃)₄ N⁺. Illustrative, but non-limiting examples of suitablethiomolybdate salts useful in producing the catalysts of this inventioninclude (n-butylamine)₂ H₂ MoS₄, (diethylamine)₂ H₂ MoS₄,tetramethylammonium thiomolybdate [(CH₃)₄ N]₂ MoS₄, ethylenediammoniumthiomolybdate H₃ N(CH₂)₂ NH₃ MoS₄ and tridodecylamine oxythiomolybdate[(CH₃ (CH₂)₄)₃ NH]HMoO₂ S₂.

It should be noted that many of the catalyst precursor salts disclosedin U.S. Pat. Nos. 4,243,553 and 4,243,554, the disclosures of which areincorporated herein by reference, will also be useful as precursors forforming the catalysts of this invention. Those skilled in the art willalso appreciate that the precursor salts suitable as starting materialsuseful for forming the catalysts of this invention are known materialswhich can be prepared by synthesis techniques reported in the art. Suchtechniques are not part of this invention. Also, in a preferredembodiment the catalyst precursor salt will be oil insoluble.

The thermal decomposition of unsubstituted ammonium thiomolybdate saltshas been reported in the J. Inorg. Nucl. Chemistry, 35, 1895-1904(1973), with the thermal decomposition of (NH₄)₂ MoO₂ S₂, (NH₄)₂ MoS₄,(NH₄)₂ WO₂ S₂ and (NH₄)₂ WS₄ being disclosed in accordance withavailable analytical techniques using a Mettler instrument and a DTA/TGAinstrument of Linseis KG, West Germany. The experiments were carried outin a nitrogen atmosphere at normal pressure employing a heating rate of6° C./min. (heating rate of 6°-10° C./min. being conventional for suchanalytical procedures). At a decomposition temperature of 400° C., MoS₂was reported as the probable composition. The materials formed by thesedecomposition procedures do not relate to the catalysts of thisinvention.

The catalysts of this invention are prepared by contacting one or morecatalyst precursor salts, in the presence of sulfur and hydrogen and ata temperature of from about 150°-600° C., with a hydrocarbon for a timesufficient to form the catalyst. Preferably, the temperature will rangefrom about 200°-500° C. and more preferably from about 300°-400° C. Therate at which the precursor is heated in the presence of the sulfur,hydrogen and hydrocarbon is not important, but it has been found that alow heating rate, i.e., below about 1° C./min. does not result in asgood a catalyst as is obtained if the heating rate is above this value.The catalysts of this invention may also be promoted with one orpromotor metals or their sulfides. Illustrative, but non-limitingexamples of useful promotor metals include iron, cobalt, nickel andmixture thereof.

X-ray powder diffraction analysis has revealed that the catalysts ofthis invention exhibit poor crystallinity. Those skilled in the art willknow that poorly crystalline materials exhibit diffuse Bragg peaks asopposed to sharp Bragg peaks exhibited by crystalline materials. Also,combustion analysis of the catalysts of this invention has shown thatthey contain nitrogen in addition to the carbon. However, the amount ofnitrogen in these catalysts is relatively minor (i.e., <1 wt. %) andvariations in the amount thereof does not seem to have any effect on theselectivity or activity of the catalysts.

The sulfur required during the formation of the catalyst must be presentin an amount at least sufficient to achieve the desired stoichiometry ofthe catalyst. However, it is preferred that the sulfur will be presentin an amount in excess of the stoichiometrically required amount. As haspreviously been stated, all or part of this sulfur may be from theprecursor salt itself (i.e., a thiomolybdate or thiotungstate).Alternatively, all or part of the sulfur may be from sulfur or asulfur-bearing compound. However, inasmuch as it is preferred thatsulfur be present in an amount in excess of the stoichiometricallyrequired amount, it is preferred that sulfur or a sulfur-bearingcompound be present irrespective as to whether or not sufficient sulfuris present in the precursor salt. The hydrogen required for forming thecatalysts of this invention may be present in the form of gaseoushydrogen, a hydrogen-bearing gas such as H₂ S, a hydrogen donor solventor combination thereof.

The hydrocarbon used for forming the catalyst of this invention may beany hydrocarbon that is convenient, other than a heavy hydrocarbonaceousoil. By heavy hydrocarbonaceous oil is meant any hydrocarbon oil havingat least 10 weight percent of material boiling above about 1050° F. atatmospheric pressure, such as various residua, whole and topped crudeoils, etc. The hydrocarbon used for forming the catalysts of thisinvention will preferably comprise an aromatic hydrocarbon or a mixtureof one or more aromatic hydrocarbons with other hydrocarbons. In fact,the catalysts of this invention may be formed in situ in asulfur-containing feed merely by contacting one or more suitableprecursor salts useful in forming the catalysts of this invention withthe feed and hydrogen at a temperature above about 150° C. andpreferably above about 200° C. After the catalyst has been formedin-situ, the catalyst will then act to remove sulfur from said feed ifhydrogen is present therein. The hydrogen may be present in the feed asgaseous hydrogen, a hydrogen-bearing gas such as H₂ S, one or morehydrogen donor hydrocarbons such as tetralin, or combination thereof.

The invention will be more readily understood by reference to thefollowing examples.

EXAMPLE 1

In this example, an ammonium thiomolybdate (NH₄)₂ MoS₄ catalystprecursor was pressed under 15,000-20,000 psi and then meshed through10/20 mesh or 20/40 mesh sieves. One gram of this meshed catalystprecursor was mixed with 10 g of 1/16-in. spheroid porcelain beads andplaced in the catalyst basket of a Carberry-type autoclave reactor. Theremainder of the basket was filled with more beads. The reactor wasdesigned to allow a constant flow of hydrogen through the feed and topermit liquid sampling during operation.

After the catalyst precursor and beads were charged to the reactor, thereactor system was flushed with helium for about 30 minutes after whichhydrogen flow through the reactor was initiated at a rate of 100 cc/min.After the hydrogen began flowing through the reactor, the reactor wascharged with 100 cc of a feed comprising a DBT/Decalin mixture which wasprepared by dissolving 4.4 g of dibenzothiophene (DBT) in 100 cc of hotDecalin. The solution thus contained about 5 wt. % DBT or 0.8 wt. % S.The hot feed solution was filtered and 1 cc of decane was added.

After the feed was charged to the reactor, the hydrogen pressure wasincreased to about 450 psig and the temperature in the reactor raisedfrom room temperature to about 350° C. over a period of about 1/2 hour.The hydrogen flow rate through the reactor was maintained at about 100cc per minute. When the desired temperature and pressure were reached, aGC sample of liquid was taken and additional samples taken at one hourintervals thereafter. The liquid samples from the reactor were analyzedusing a Perkin-Elmer 900 Gas Chromatograph. The composition of thecatalyst produced was analyzed for sulfur and carbon by combustion inoxygen at 1600° C. and analyzing the so-formed SO₂ and CO₂ by infraredspectroscopy and thermal conductivity, respectively. By the time atemperature of 350° C. was reached in the reactor, a catalyst had beenformed in-situ which had the following composition:

    MoS.sub.1.93 C.sub.0.94

After the catalyst had been formed it was found to be stable and nofurther change in its composition took place over an eight hour periodthat the system was maintained at 350° C. and 450 psig. Further, duringthe formation of the catalyst, little if any hydrodesulfurization of theDBT in the feed took place.

As the reaction progressed, samples of liquid were withdrawn once anhour and analyzed by GC chromatography in order to determine theactivity of the catalyst towards hydrodesulfurization as well as itsselectivity for hydrogenation. The hydrodesulfurization activity wasdetermined according to the following model reaction: ##STR1## Thehydrodesulfurization zero order rate constant, r, for the catalystproduced from the in-situ decomposition of the ammonium thiomolybdatewas found to be 30×10¹⁶ molecules of DBT desulfurized per gram ofcatalyst per second. In the rest of the examples, most of thehydrodesulfurization zero order rate constants are normalized to thiscase for which the HDS activity is set as equal to 100.

The selectivity factor, f, was also determined and is defined in view ofthe model reaction as the ratio of the hydrogenated products to thetotal desulfurization as follows: ##EQU1## It should be noted that theamount of BC produced according to the model reaction was not includedin determining the selectivity factor, because the amount of BC producedwas always less than 2%. In this experiment, the selectivity factor, f,was found to be 50. The results of this experiment are also contained inTable 1.

This experiment thus establishes the in-situ formation of a catalyst ofthis invention and its usefulness for both hydrodesulfurization andhydrogenation.

EXAMPLE 2

This experiment was similar to that in Example 1, except that thecatalyst precursor was ethylene diammonium thiomolbydate (H₃ N(CH₃)₂NH₃)MoS₄. The in-situ catalyst formmed had the composition:

    MoS.sub.1.8 C.sub.2.3

The relative HDS activity, r, of the catalyst was 82 with theselectivity factor, f, being 25. These results are also listed inTable 1. FIG. 1 illustrates the unusual por volume distribution of thiscatalyst.

EXAMPLE 3

This experiment was similar to that of Example 2, except that thecatalyst precursor was ethylene diammonium molybdate (H₃ N(CH₂)₂NH₃)MoO₄. This produced a catalyst having the following composition:

    MoS.sub.1.9 C.sub.0.96

The relative HDS activity of this catalyst was found to be 95 with aselectivity factor of 43. These results are also contained in Table 1.

EXAMPLE 4

This experiment was similar to that of Example 1 except that thecatalyst precursor was tetrabutylammoniumthiomolybdate [(CH₃ (CH₂)₃)₄ ]₂MoS₄ which formed a catalyst in-situ having the following composition:

    MoS.sub.1.79 C.sub.2.8

The surface area of this catalyst was measured using the BET method andwas found to be about 152 M² /g. The HDS activity and selectivityfactors were found to be 305 and 49, respectively, which data is alsopresented in Table 1. Data for the pore volume, average pore size andpore distribution for this catalyst are presented in Table 3.

EXAMPLE 5

This experiment was identical to that of Example 1 except that thecatalyst precursor was tridodecylammonium oxythiomolybdate (CH₃(CH₂)₁₁)₃ NHMoO₂ S₂ which produced a catalyst in-situ having acomposition:

    MoS.sub.1.98 C.sub.2.7

BET analysis of the catalyst revealed it to have a surface area of 243M² /g. The relative HDS activity of 145 and the selectivity factor was15. This data is also presented in Table 1. FIG. 2 illustrates theunusually narrow pore volume distribution of this catalyst.

EXAMPLE 6

This experiment was identical to that of Examples 1-5 except that thecatalyst precursor was tridodecylammonium molybdate (CH₃ (CH₂)₁₁)₃NHMoO₄, which produced a catalyst in-situ having the compositionMoS₁.2-1.7 C₁.4-1.8. The relative HDS activity was 132 and theselectivity factor was 34. BET analysis of this in-situ producedcatalyst showed that it had an area of 230 M² /g. Data relating to porevolume and pore size distribution are given in Table 3.

EXAMPLE 7-9

These experiments were identical to those of Examples 1-5, with theexception that the catalyst precursor was first dried in helium at atemperature of from between 100°-150° C. for a period ranging from about24-72 hours. The catalyst precursors were ammonium thiomolybdate, (NH₄)₂MoS₄, n-dodecylaminethiomolybdate CH₃ (CH₂)₁₁ NHMoS₄, andtridodecylammonium oxythiomolybdate (CH₃ (CH₂)₁₁)₃ NH₂ MoSO₃ whichproduced in-situ catalysts having the following respective compositions:

    MoS.sub.1.85 C.sub.0.29, MoS.sub.1.79 C.sub.0.76 and MoS.sub.1.5-2.0 C.sub.1.7-2.2.

The BET surface area of the catalyst formed from the tridodecylammoniumoxythiomolybdate was 364 M² /g. Data on the pore volume and pore sizedistribution of this catalyst are presented in Table 3. The relative HDSactivities and selectivity factors are given in Table 2.

Comparison of the data in Table 2 with that in Table 1 shows thatalthough the carbon content of the catalysts formed from the heliumpre-dried precursors was slightly different than if they had not beendried, both the relative HDS activities and the selectivities weresubstantially the same for both cases.

EXAMPLE 10

In this experiment, 2 grams of ammonium thiomolybdate were refluxed intetralin under nitrogen for between four and eight hours and a blackcatalyst powder was recovered which was washed in tetralin and analyzedaccording to the procedure set forth in Example 1. The composition ofthis ex-situ formed catalyst was found to be MoS₂.99 C₁.34. The catalystwas pelletized to a 20/40 Tyler mesh, mixed with beads, etc. and placedin the Carberry-type reactor with the DBT/Decalin mixture, etc.following the procedure in Example 1. The relative HDS activity was 95and the selectivity factor was 34.

EXAMPLE 11

This experiment was identical to that of Example 10, except that thecatalyst precursor was tridodecyl ammonium molybdate (see Example 6)which was refluxed in tetralin under a blanket of H₂ S. The compositionof the catalyst initially formed ex-situ was found to be MoS₀.7 C₉.4which had a relative HDS activity of 259 and a selectivity factor of 27.Subsequent analysis of the catalyst after being "on-stream" in thereactor for 8 hours revealed a substantial change in its sulfur andcarbon content, which is probably due to the catalyst changing to a morestable equilibrium phase in the reactor (compare to Example 6).

EXAMPLE 12

This example demonstrates the effectiveness of promoting the catalystsof this invention with a Group VIII metal, which in this particular casewas cobalt. The catalyst used was that produced in Example 5 by thein-situ decomposition of tridodecyl ammonium oxythiomolybdate which hada relative HDS activity of 145 and selectivity of 15. This catalyst waspromoted by soaking in an acetone solution of Co(NO₃)₂ followed bydrying and then presulfiding with an 85/15 mixture of H₂ /H₂ S at 400°C. for two (2) hours. This resulted in the catalyst containing 8 wt. %of Co as cobalt sulfide, based on the total catalyst weight.

The 8% cobalt promoted catalyst was then placed back into the reactorand was found to have a relative HDS activity of 349 with a selectivityfactor of 8 after eight hours on-stream. This 8% Co promoted catalystwas then recovered, washed with Decalin and dried by placing in a vacuumoven at 50° C. The dry catalyst was then impregnated a second time withthe Co(NO₃)₂ acetone solution and sulfided as before (H₂ /H₂ S) to yielda catalyst containing 12 wt. % Co as cobalt sulfide. This catalyst wasplaced back in the reactor and was found to have a relative HDS activityof 255 with a selectivity of 6. By way of comparison, a standard cobaltmolybdate on alumina HDS catalyst in commercial use had a relative HDSactivity of 100. The results of this experiment are summarized in Table4.

                                      TABLE 1                                     __________________________________________________________________________    Catalysts Produced by In-Situ Decomposition of Ammonium Salts                 Cation                                                                        Anion*                                                                              (NH.sub.4).sup.+                                                                     (H.sub.3 N(CH.sub.2).sub.2 NH.sub.3).sup.2+                                             (CH.sub.3 (CH.sub.2).sub.3).sub.4 N.sup.+                                              (CH.sub.3 (CH.sub.2).sub.11).sub.3                                            NH.sup.+                                      __________________________________________________________________________    MoS.sub.4.sup.2-                                                                    MoS.sub.1.93 C.sub.0.94                                                              MoS.sub.1.8 C.sub.2.3                                                                   MoS.sub.1.79 C.sub.2.8                                 r     100    82        305                                                    f      50    25         49                                                    MoO.sub.2 S.sub.2.sup.2-        MoS.sub.1.98 C.sub.2.7                        r                               145                                           f                                15                                           MoO.sub.4.sup.2-                                                                           MoS.sub.1.9 C.sub.0.96                                                                           MoS.sub.1.2-1.7 C.sub.1.4-1.8                 r            95                 132                                           f            43                  34                                           __________________________________________________________________________     *NOTE:                                                                        r is normalized HDS zero order rate constant and f is the selectivity         factor as defined in Example 1.                                          

                  TABLE 2                                                         ______________________________________                                        Catalysts Produced by In-Situ Decomposition                                   of Ammonium Salts Pre-dried in Helium                                         Cation                                                                        Anion* (NH.sub.4).sub.2.sup.2+                                                                  CH.sub.3 (CH.sub.2).sub.11 NH.sub.3.sup.+                                                  (CH.sub.3 (CH.sub.2).sub.11).sub.3             ______________________________________                                                                       NH.sup.+                                       MoS.sub.4.sup.2-                                                                     MoS.sub.1.85 C.sub.0.29                                                                  MoS.sub.1.79 C.sub.0.76                                     r      95         182                                                         f      40          53                                                         MoSO.sub.3.sup.2-      MoS.sub.1.5-2.0 C.sub.1.7-2.2                          ______________________________________                                         Note: See note in Table 1.                                               

                                      TABLE 3                                     __________________________________________________________________________    Unusual Catalyst Pore Volume Distributions                                    __________________________________________________________________________    Precursor                                                                              [(CH.sub.3 (CH.sub.2).sub.3).sub.4 N].sub.2 MoS.sub.4.sup.a                               (CH.sub.3 (CH.sub.2).sub.11).sub.3 NH.sub.2 MoO.sub.4                         .sup.b       (CH.sub.3 (CH.sub.2).sub.11).sub.3                                            NH.sub.2 MoO.sub.3 S.sub.1.sup.c            Surface Area                                                                           152 m.sup.2 /gm                                                                           230 m.sup.2 /gm                                                                            364 m.sup.2 /gm                             Pore Volume                                                                            0.0986 cc/gm                                                                              0.6889 cc/gm 0.8982 cc/gm                                Average Pore Size                                                                      25.9 Å  119.92 Å 98.6 Å                                  Pore Distribution                                                             1200-600             26.5         9.5                                         600-400              9.9          6.9                                         400-400              5.4          4.4                                         300-250              3.1          3.1                                         250-200              3.7          3.8                                         200-150              4.6          4.5                                         150-100              8.8          8.7                                         100-50               17.6         31.8                                        50-20    100%        20.4         27.1                                        __________________________________________________________________________     Notes:                                                                        .sup.a See Example 4                                                          .sup.b See Example 6                                                          .sup.c See Example 9                                                     

                  TABLE 4                                                         ______________________________________                                        COBALT PROMOTED CATALYSTS                                                     Catalyst           Relative HDS Activity                                      ______________________________________                                        Conventional Co/Mo on Al.sub.2 O.sub.3                                                           100                                                        MoS.sub.1.98 C.sub.2.7                                                                            42                                                        MoS.sub.1.98 C.sub.2.7 + 8% Co                                                                   349                                                        MoS.sub.1.98 C.sub.2.7 + 12% Co                                                                  255                                                        ______________________________________                                    

EXAMPLE 13

This Example demonstrates how the process of U.S. Pat. No. 4,243,553does not produce the catalysts of this invention. In this example, 1gram of n-dodecylamine thiomolybdate (CH₃ (CH₂)₁₁ NH₂)₂ MoS₄ wasthermally decomposed by heating at 400° C. in flowing helium for 1 hourwhich yielded a black powder having a BET surface area of 243 m² gm. Thecarbon content of the decomposed product was 17.1% yielding a value forz' of 3.3 which lies outside the value of z' for catalysts of theinstant invention.

The same procedure was used as in Example 1. That is, the decompositionproduct was pelletized, crushed to a 20-40 mesh size and put in anautoclave containing 100 ml of decalin which contained 5 wt. %dibenzothiophene (DBT). Hydrogen was introduced into the autoclave at aflow rate of 100 cc/min and a pressure of 450 psi and the temperature inthe autoclave was maintained at 350° C. for eight hours which yielded acatalyst having a rate constant of only 10.5×10¹⁶ molecules of DBTdesulfurized per gram of catalyst per second.

Not only does this show that the process in U.S. Pat. No. 4,243,553 doesnot produce the catalysts of this invention, it also shows that highsurface area of itself does not produce a good catalyst.

The above experiment was repeated but with the precursor decomposed inhelium at 600° C. This also resulted in an unsatisfactory catalysthaving a rate constant of only 9.2×10¹⁶.

EXAMPLE 14

This example demonstrates the necessity of contacting the catalystprecursor with both a hydrocarbon and sulfur at the same time, atelevated temperature, in order to form a catalyst of this invention. Inthis experiment, a 1 gram sample of tridodecylamine molybdate wasrefluxed in tetralin for 18 hours at about 206° C. A black powder wasproduced which was then contacted with a mixture of 15% H₂ S in H₂ for10 hours at 350° C. This produced a molybdenum disulfide product whichhad a value of 30 for z' which is outside the scope of the value for z'for catalysts of this invention. This product was then washed withDecalin, pelletized and placed in the Carberry reactor with theDBT/Decalin feed following the procedure in Example 1. After being onstream i the reactor for 11 hours, the black powder was found to have arate constant of only 10.6×10¹⁶.

EXAMPLE 15

This example also demonstrates the necessity of contacting the catalystprecursor, at elevated temperature, with hydrogen, a hydrocarbon andsulfur at the same time in order to form a catalyst of this invention.In this experiment, a 1 gram sample of tetrabutylammonium thiomolybdate(see Example 4) was placed in a quartz tube in a muffle furnace at 350°C. and a flowing mixture of 15% H₂ S in H₂ was contacted with theprecursor for about 7 hours. The resulting powder which had a surfacearea of only 0.8 M² /g, was then washed with Decalin, pelletized, etc.,and placed in the Carberry reactor with the DBT/Decalin feed and, afterbeing on stream for about 11 hours, was found to have ahydrodesulfurization activity of only 1.7×10¹⁶.

EXAMPLE 16

This example was similar to Example 14, except after the tridodecylminemolybdate was refluxed in tetralin and washed with Decalin, it was thenplaced in the DBT/Decalin feed in the Carberry reactor without theintermediate hydrogen sulfide treatment. The so-formed catalyst had anHDS rate constant of only 3.9 ×10¹⁶ and was essentially molybdenumdisulfide with a BET surface area of 300 m² /g. The z' value of thecatalyst was 30.

EXAMPLE 17

This example demonstrates the effectiveness of the catalysts of thisinvention for hydrodenitrogenation. In this example, a catalyst of thisinvention was formed in-situ from a tetrabutylammoniumthiomolybdateprecursor using the procedure set forth in Example 4. After the catalysthad been formed in-situ in the reactor, it was removed from the reactor,washed with fresh Decalin and placed back in the reactor with a freshfeed of 5 wt. % DBT in Decalin to which had been added 1100 ppm ofnitrogen as Quinoline. The temperature and pressure in the reactor werethen brought up to 325° C. and 450 psi of hydrogen at a hydrogen flowrate at about 100 cc/min. The reactor was maintained at these conditionsfor six hours and a sample of the feed was removed from the reactorevery hour and analyzed for nitrogen.

The results are shown in FIG. 3. The hydrodenitrogenation rate constantfor the catalyst was calculated to be:

    k.sub.HDN =-0.21 hr.sup.-1.

Also, after the six hours onstream, the feed was measured for sulfur andthe results indicated that 5 wt. % of the DBT in the feed had beendesulfurized.

Repeating this experiment with a fresh sample of catalyst and feed at atemperature at 350° C. resulted in a hydrodenitrogenation rate constantk_(HDN) =-0.33 hr⁻¹ and 10 wt. % of the DBT originally present in thefeed had been desulfurized after the six hours. The results of this 350°C. run are shown in FIG. 4.

EXAMPLE 18

This experiment was similar to that of Example 17, except that thecatalyst was formed in-situ in the reactor from a tridodecylammoniummolybdate precursor. Two runs were made, one at 325° C. and one at 350°C. as was done in Example 20. The results of these two runs are shown inFIGS. 5 and 6. At 325° C., the hydrodenitrogenation rate constantk_(HDN) =-0.1 hr⁻¹ and 5 wt. % of the DBT in the feed had beendesulfurized after the sixth hour. At 350° C., the hydrodenitrogenationrate constant k_(HDN) was found to be -0.17 hr⁻¹ and 10 wt. % of the DBTinitially present in the feed had been desulfurized after the sixthhour.

EXAMPLE 19

In this example, both the hydrodenitrogenation and hydrodesulfurizationrate constants of a conventional nickel molybdate on aluminahydrotreating catalyst were determined. A typical hydrotreating catalystwas prepared by impregnation and calcination techniques well-known tothose of the art to produce a catalyst containing b 4.5 wt. % CoO, 15.9wt. % MoO₃, and 0.8 wt. % P₂ O₅ with the balance being a reforming gradeof α-Al₂ O₃. This catalyst was placed in the same reactor with the samefeed and found to have a hydrodenitrogenation rate constant k_(KDN) of-0.07 hr⁻¹ with a relative HDS activity of 28.7.

EXAMPLE 20

This experiment was similar to that of Example 4 except that thecatalyst precursor was tetrabutylammonium thiotungstate [(CH₃(CH₂)₃)₃)₄)N]₂ WS₄. The HDS activity rate constant and the selectivityfactor were found to be 19.6×10¹⁶ and 50, respectively.

EXAMPLE 21

This experiment illustrates the effect of the chain length of the alkylradical in the catalyst precursor salt on the properties of the catalystformed from the precursor. In this experiment, which was similar to thatof Example 1, the activities of catalysts formed from varioustetralkylamine thiomolybdate precursor salts were compared. The HDSactivities and selectivities are presented in Table 5 and show that, ingeneral, longer radicals resulted in better catalysts. Powder X-raydiffraction data of the catalysts showed that increasing the alkyl chainlength of the precursor salt resulted in decreasing the crystallinity ofthe catalyst. However, all of the catalysts were poorly crystallineaccording to the X-ray data.

                  TABLE 5                                                         ______________________________________                                        Tetralkylamine Radical                                                        of Precursor Salt*   r      f                                                 ______________________________________                                        Tetramethyl          30.7   52.5                                              Tetraethyl           12.7   53.0                                              Tetrabutyl           42.0   55.5                                              Tetrapentyl          72.5   34.3                                              ______________________________________                                         *All thiomolybdates.                                                     

What is claimed is:
 1. A process for forming a carbon-containing, poorlycrystalline metal sulfide catalyst which comprises contacting one ormore catalyst precursor salts, in the presence of sulfur and hydrogenand at elevated temperature, with a hydrocarbon for a time sufficient toform said catalyst wherein said precursor salt has the formula B_(x)[MO_(y) S_(4-y) ] wherein x is 1 or 2 and y is any value between 0 and4, wherein M is Mo or W and wherein B is (a) an ammonium ion, or (b) analkyl or aryl ion wherein said ion may contain from 1-4 alkyl or arylgroups.
 2. The process of claim 1 wherein said elevated temperature isat least about 150° C.
 3. The process of claim 2 wherein saidhydrocarbon comprises an aromatic hydrocarbon.
 4. The process of claim 3wherein said elevated temperature ranges from about 200° to 600° C. 5.The process of claim 4 wherein said catalyst has the formula MS_(2-z)C_(z') wherein 0.01≦z<0.5 and 0.01≦z' ≦3.0 and wherein M is selectedfrom the group consisting of W, Mo and mixtures thereof.
 6. A processfor forming a nitrogen and carbon-containing, poorly crystalline metalsulfide catalyst which comprises contacting one or more catalystprecursors selected from the group consisting essentially of (a)ammonium thiomolybdate or thiotungstate salts, (b) ammonium molybdate ortungstate salts, (c) substituted ammonium thiomolybdate or thiotungstatesalts, (d) substituted ammonium molybdate or tungstate salts andmixtures thereof, with sulfur, hydrogen and a hydrocarbon at atemperature of at least about 150° C. for a time sufficient to form saidcatalyst.
 7. The process of claim 6 wherein nitrogen is present in saidso-formed catalyst in an amount of less than about one weight percent.8. The process of claim 7 wherein said hydrocarbon comprises an aromatichydrocarbon.
 9. The process of claim 8 wherein said elevated temperatureranges between 200° to 600° C.
 10. The process of either of claims 6, 7,8 or 9 wherein the catalyst is promoted with one or more promotermetals.
 11. The process of claim 10, wherein said promoter metalscomprise iron, nickle, cobalt and mixtures thereof.
 12. The process ofclaim 11 wherein said elevated temperature ranges from about 300° to400° C.